I've been having the same miserable problems, hanging up, accidentally hitting mute, dialing random numbers, which I notice no one can hear me when I push them by accident with my cheek, as well as accidentally hitting the blue tooth button with my cheek, which I notice I can't hear the person until I figure out that's what I did
urgh!! But I've learned how to fix it.
So here's a mini solution I found... once u place the call (or answer a call) hit the lock button on the top right, which is also the power button. What will happen is it will temporarily lock your phone (the screen will go totally dark & you can bump it with your cheek & it will not light up). When you move it about 2inches away from your face, it will unlock... so you will have to get used to repeatedly locking it (if you have a habit of moving that much), but HERE'S THE GOOD NEWS... for the most part, it should stay locked. I noticed it doesn't unlock unless you really move it far away from your face. I've tried & tested it. I moved around, bumped it with my cheek, touched it while it was on my ear, and I even held the phone against my ear with my shoulder (instead of my hand), and it still stayed locked (& the screen was still totally dark).
Once I moved it about 1-2 inches away from my face, that's when it lit up & became unlocked & the buttons were once again pressable. I believe they made the phone like this so that it would be easy to access the keypad without having to unlock your phone. So when your phone thinks you are about to dial or access the buttons, it automatically locks for you. It's a responsive/reactive phone. It will react to your motions. (If you ever seen a website that has a popup every time you are about to exit out of the site, think of this phone like that.) When the phone thinks you are about to hang up or dial a button, it unlocks. So if you don't want that to happen, then as soon as you see it unlock (& the screen lights up), just hit the lock button, and it will be locked again.
